The present invention relates to a combustion chamber for a turbojet engine, more particularly such a combustion chamber having an annular fuel injector to reduce pollutants from the engine.
Gas turbine engines having annular combustion chambers are well known in the art, particularly such engines utilized on aircraft, and conventionally comprise air and fuel injecting systems located in the forward portion of the combustion chamber. Such known fuel injection systems comprise feeder bowls circumferentially arrayed around an axis of symmetry at the front end of the combustion chamber, wherein each feeder bowl comprises a fuel injector, a swirler for the fuel atomizing air and an array of holes to inject air into the atomized fuel cone. Such feeder bowls are typically circular in configuration and the number of such fuel injectors around the annular combustion chamber is rather substantial.
While generally successful, the known structures have a "dead" zone between each bowl within the combustion chamber resulting in a circumferential temperature profile that is non-homogeneous. Such "dead" zones generate nitrogen oxides (NO.sub.x) in the engine exhaust gases.
U.S. Pat. No. 2,920,449 discloses an annular combustion chamber wherein the forward chamber end comprises an annular opening bounded by two, spaced apart cylindrical walls, the air axially entering the chamber through the opening. An injection manifold comprising two rings having radial orifices is mounted in the annular opening and a diverging annulus is located rearwardly of the injection manifold to separate the combustion gases issuing from the combustion zone of the combustion chamber into two annular flows, one directed at the inner wall, the other directed at the outer wall.
French Patent No. 2,698,157 discloses a combustion chamber having an injection system utilizing feed bowls having an elliptical configuration. This design reduces the number of injectors necessary and improves the homogeneity of the circumferential temperature profile.